Overheating! Parts replaced: Radiator, Sensors, Thermostat, Relay, Fuses. NOT leaking or boiling over! YES, fans are working! W/in 5 blocks its HOT! Ran w/o therm did NOT overheat 1994 Toyota Corolla

do a compression test
have the radiator flow tested by a reputable shop
check the fins on the radiator--flaking and falling off --replace
check transmission for over heating (automatics) check fan operation (replace viscous fan hub or check coolant temp sensor, 2 fuses and fan relay is electric)
run fault codes to check for fuel sensor failures
check cat converters for blocking exhaust system
check for good radiator cap
have the cooling system pressure tested for leaks
Just a few of the items that cause overheating

blocked radiator, blown head gasket, new thermostat in wrong
If the overheating is occurring at standing , low speeds or high rpm low road speed conditions , replace the viscous fan hub as it is not driving the fan properly
If you have electric fans check
bot fuses, engine coolant sensor, relay, fans and wiring

see a mechanic

ok check these things #1 check for leaks at the radiator #2 water pump for leaks#3 check for freeze plug leak#4 check to see if your cooling fan works#5 check to make sure the water jug is not leaking#6 fill the radiator with water then start your engine and try to see if you can tell if the water flows,if its not flowing check the thermostat,now you can check the thermostat by putting it down in some boiling hot water if while in the hot water it contracts its ok but i would replace it because it is work to go back to do so,check your radiator cap also,now if the fans are the problem then you should change the coolant temp sensor for the fans ,now i hope after making these check you will be able to solve the problem

there are many causes of overheating.

first off is you didnt stated engine option (size)

the engine can make excessive heat too. (late timing)

1: bad thermostat. 190 is ok, but it can be bad, even a new one.

try a quality brand like STANT, not dura . etc.

2: it must hold pressure, bad cap>? 12-15 psi

3: gee, did use 50% AF. it will not run right with out AF antifreeze.

4: bad water pump. running old AF causes the impeller to rust to nothing.

5: thermostat up side down, or bleed hole not up hill (jiggle pin,etc)

6: pressure in the hose , does NOT prove flow. only pressure.

7: air flow to RAD bocked, (at A/C condensor or between)

8: bad fan and related parts, varies by engine option not stated.

9: bad fan controls. same.

10: seem like it overheats even PARKED. right? never moved.

11: if it dont overheat moving fast this is a BIG clue. but nobody wants to take that risk of 10 is true. sure.

12: air in block, did you , ignore the side tank and look in side rad for full of AF 100% by pulling cap cold, over and over, each cold cycle

until dead sure its FULL???????

13: BAD TEMP GUAGE, DID YOU USE AN IR PYYO GUN to prove the thing is really overheating

14: is it boiling over, that is steam or hot water blasting to the expansion side tank???? signs/ got real signs of overheating?



15: passes rad leak down test?

16: passes exhaust leak test to rad test? green/blue checked?

17: steam out tail pipe end hot?

18: pinging, (too hot sighs)

19: OBD2 scan tool shows, 240 and the dash gauge and the pyro gun

all agree its 240"

20: sludge packup on sides of water jackets, seen when pump was pulled and NOT CORRECTED (flushed>?)



at the least.

ok one more , fan belts slip?

replace thermostat.then bleed coolant system, this is how you do it.fill the cooling coolant system with 50 / 50 dexcool and water to raise boiling point,straight water will evaporate boil away cause engine to overheat catch fire thats why you need 50 / 50 mixture antifreeze and water.to bleed coolant system first fill coolant system until coolant stay at the full cold mark on the the coolant overflow jug,then you start engine allow it to idle,place the heater and ac control in any ac setting except max and the temperature control to the highest setting,run engine until lower hose to water pump is hot. with the engine hot run the engine speed up to 3000 rpm and allow it return to idle, repeat this 5 times. slowly open the bleed valve on the thermostat housing or look for bleed valve at the water pump heater hose.open bleed valve for 15 seconds to expel any trapped air.then top off the coolant as necessary,and when top radiator hose hot thermostat open up.keep adding cooling to overflow until coolant level stop at full cold mark dont over fill coolant.if engine seem like overheating while looking at cooling gauge turn off engine wait a while until cool off add more coolant until coolant level stay stable and dont drop any.when open radiator overflow cap use large rag over the radiator cap to keep from getting scald open radiator cap a little at a time but dont open radiator cap until engine cool down first.replace the radiator overflow cap, thermostat,and engine coolant temperature sensor and check the cooling fans fuses and relays see what happens.

Now that you've eliminated the thermostat, it could be a number of other things. Don't drive the car too far until you've fixed the overheating problem - overheating can destroy an engine.

That split ribbed hose you see is plastic wire loom - it carries and protects electrical wires, and is not the cause of overheating.

1. Low coolant level
2. Radiator hose split/cracked, causing low coolant level.
3. Head Gasket - leaking, causing low coolant level
4. Thermostat - stuck closed (you eliminated this possibility)
5. Radiator cap - worn/damaged
6. Radiator fins - obstructed by debris/cardboard
7. Water Pump belt - missing/broken
8. Heater Core - leaking, causing low coolant level
9. Intake Manifold Gasket - leaking, worn, damaged
10. Radiator Fan Relay - faulty
11. Radiator Fan Blade - broken, missing
12. Radiator Fan Sensor/Switch - faulty
13. Water Pump - leaking, causing low coolant level
14. Radiator Fan Motor - faulty

My primary suspects would be Rad Fan Relay (#10), and
Rad Fan Switch (#12).

Does the top rubber engine to radiator hoes get hot? If yes then the new thermostat is working. Does the bottom return hose from the radiator back to the engine also get hot? If yes then the pump is OK. If not then there is a blockage in the system and this will need to be flushed out from both the radiator and the engine block using a high pressure hose. Does the radiator fan come on promptly. It should start before the bottom return hose becomes hot. If not then the temperature sensor (different from the temperature sender to the dash display) maybe at fault. Your relay maybe fine but it is the sensor that actually triggers the fan to come on. It may be just bad connection so try wiggling the wires to it when the engine has got warm. The temperature sensor is also important to let the engine computer management system (ECU)know that the engine has reached operating temperature. A failed sensor not only allows overheating but means that the ECU thinks the engine is still cold and runs the engine on a rich mix. Have you noticed lumpy idling when hot and excessive fuel consumption recently? these are symptomatic of a failing sensor.

if it's coming from the radiator cap your car is overheating,two things could be wrong
#1 thermostat is stack and is not circulating or
#2 that your actuator switch is not engaging the
fan

Ford 2000 Taurus

To solve the problem you have the things to do in this order;

) When the engine is cold top off the radiator with fluid. (When the pump was replaced the fluid should have been also)
) Make sure the radiator fluid has anti-freeze in it. This is also anti boil also !
) Add fluid to the overflow reservoir.
) Make sure the drive belt was replaced on the water pump.
) With the engine running, you can add fluid to the radiator for the first minute or so. You want to get air pockets out.
) Replace radiator cap.
) Let car warm up. When it's hot you should get the radiator fan coming on.
) When it get hotter the air-conditioning fan may come on.
) If the fan does not come on, the heat sensor is probably bad.
) If all fans come on, and it overheats, you may have a bad thermostat. Trace the upper radiator hose to where it connects to the engine. That's where it located.

Do not operate the engine when it overheats, You will damage the head gaskets and cause radiator fluid to leak into the cylinders.
If you smell radiator fluid in the exhaust fumes, it may already be leaking.